论文标题
高度掺杂的N型GE中的相填充奇点的应变影响
Strain effects on Phase-Filling Singularities in Highly Doped n-Type Ge
论文作者
论文摘要
最近，Chi Xu等。 predicted the phase-filling singularities (PFS) in the optical dielectric function (ODF) of the highly doped $n$-type Ge and confirmed in experiment the PFS associated $E_{1}+Δ_{1}$ transition by advanced \textit{in situ} doping technology [Phys.莱特牧师。 118，267402（2017）]，但是$ e_ {1} $和$ e_ {1}+δ_{1} $之间的强重叠使$ e_ {1} $光学转变使PFS相关的$ e_ {1} $过渡发生在高掺杂浓度上，在其测量中无法观察到。在这项工作中，我们研究了在[100]，[110]和[111]晶体方向的单轴和双轴拉伸应变的情况下，高度掺杂的N型GE的PFS。与放松的散装GE相比，沿[100]的拉伸应变增加了$ e_ {1} $和$ e_ {1}+δ_{1} $过渡之间的能量分离，从而在光学测量中揭示了PFS相关的$ e_ {1} $过渡。此外，沿[110]和[111]的拉伸应变的应用提供了降低观察到PFS所需的掺杂浓度的可能性，从而产生了与$ e_ {1}+δ_{1}+δ_{1} $在unodevivalent $ l $ valleys上的过渡相关的新其他功能。在实验中可以更方便地观察到具有更方便的单轴和双轴拉伸应变的理论谓词，具有更明显的光学转变特征，从而在掺杂的半导体中为激发态提供了新的见解。
Recently, Chi Xu et al. predicted the phase-filling singularities (PFS) in the optical dielectric function (ODF) of the highly doped $n$-type Ge and confirmed in experiment the PFS associated $E_{1}+Δ_{1}$ transition by advanced \textit{in situ} doping technology [Phys. Rev. Lett. 118, 267402 (2017)], but the strong overlap between $E_{1}$ and $E_{1}+Δ_{1}$ optical transitions made the PFS associated $E_{1}$ transition that occurs at the high doping concentration unobservable in their measurement. In this work, we investigate the PFS of the highly doped n-type Ge in the presence of the uniaxial and biaxial tensile strain along [100], [110] and [111] crystal orientation. Compared with the relaxed bulk Ge, the tensile strain along [100] increases the energy separation between the $E_{1}$ and $E_{1}+Δ_{1}$ transition, making it possible to reveal the PFS associated $E_{1}$ transition in optical measurement. Besides, the application of tensile strain along [110] and [111] offers the possibility of lowering the required doping concentration for the PFS to be observed, resulting in new additional features associated with $E_{1}+Δ_{1}$ transition at inequivalent $L$-valleys. These theoretical predications with more distinguishable optical transition features in the presence of the uniaxial and biaxial tensile strain can be more conveniently observed in experiment, providing new insights into the excited states in heavily doped semiconductors.
